1. Field of the Invention
The present invention relates, in general, to a wireless communication system. More particularly, the invention relates to the technology which is effectively employed to the layout technique of internal circuits of a reception integrated circuit for the wireless communication in which the high frequency characteristics become excellent.
2. Description of the Related Art
In a signal processing integrated circuit (IC) in a wireless communication system (a terminal apparatus of a wireless communication mobile body; it will hereinafter also be referred to as “a terminal apparatus” for short, when applicable) such as a digital cellular system, a large number of internal circuits are incorporated in a signal semiconductor chip.
The signal processing IC, for example, is described in an article of “DIGEST OF TECHNICAL PAPERS”, ISSC98/Feb. 5, 1998, pp. 48 to 49, pp. 441 “A SINGLE-CHIP CMOS TRANSCEIVER FOR DCS1800 WIRELESS COMMUNICATIONS”. In this article, there is disclosed an IC in which a DCS (Digital Cellular System) 1800 oriented transmitting and receiving circuit is formed in one chip. In accordance with the layout photograph, a power source line or a ground line is present in the inside of the line of electrode terminals (pads), and LNA (Low-Noise Amplifier) circuits are arranged in the inside of the power source line or the ground line, and a power source line or a ground line is arranged in the inside of the LNA circuits.
In addition, the similar technique is described in an article of “DIGEST OF TECHNICAL PAPER”, ISSC99/Feb. 16, 1999, pp. 224 to 225, pp. 463 “DUAL-BAND HIGH-LINEARITY VARIABLE-GAIN LOW-NOISE AMPLIFIERS FOR WIRELESS APPLICATIONS”. In this article, there is disclosed an IC wherein two low-noise amplifiers, which are oriented to a 0.9, 2.0 GHz oriented dual band wireless communication transmitting/receiving IC, are formed in the one chip, and electrostatic discharge protection circuit are additionally provided therein, and also these constituent elements are all encapsulated in a TSSOP (Thin Small Outline Package) 20 pins-package. In accordance with the layout photograph, there exists a power source line and a ground line at the periphery of the circuitry, pads arranged at the inside of the periphery, the power source line and the ground line layed out inside the pads and the LNA circuit arranged inside the power source and the ground lines.
Further, as for other related application, there is a U.S. patent application Ser. No. 09/547,915 filed on Apr. 11, 2000 entitled “SEMICONDUCTOR INTEGRATED CIRCUIT” by Takikawa et al., the disclosure of which is incorporated herein by reference.
In addition, in an article of “HITACHI REVIEW”, Vol 81, No. 10 (October, 1999), pp. 17 to 20, there is described a signal processing IC in which the transmitting and receiving units including an LNA and a dual synthesizer are formed in one chip. In this article, there is described an IC for a dual band mobile telephone capable of carrying out a GSM (Global System for Mobile Communications) and the signal processing for a DCS 1800. In the GSM, the signal received through an antenna is filtered by a band-pass filter which eliminates the unnecessary signal components to extract a signal of 925 to 960 MHz. Then, the signal is amplified by the dedicated LNA circuit. Also, in the DCS 1800, the signal received through an antenna is filtered by a band-pass filter which eliminates, the unnecessary signal components to extract a signal of 1805 to 1880 MHz. Thereafter, the signal is amplified by the dedicated LNA circuit.
In the wireless communication system, since the low-noise amplifier (hereinafter, referred to as “the LNA” for short, when applicable) amplifies a received signal having a very small amplitude by a circuit in a first stage of the receiving system to send the amplified signal to a mixer as a next stage, the LNA controls greatly the whole characteristics of the receiving system. Therefore, the high frequency characteristics such as the high gain and the low noise are required for the LNA. As to the factors of degrading these characteristics, the following two points are considered.
(1) The negative feedback amount is increased and the gain is reduced due to the parasitic inductance of the wire connected to the emitter pad of a transistor constituting the LNA, and the leads extending over the inside and the outside of the package.
(2) If the wiring distance from the above-mentioned pad up to a base of the transistor constituting the LNA circuit is long, then the wiring capacitance is increased, the gain is reduced, and also the noise characteristic is degraded due to the increase of the wiring resistance.
On the other hand, in the conventional signal processing IC, there are the following problems.
(a) In the case of the conventional signal processing IC having a power source line and a ground line arranged between the edge portion of the semiconductor chip and pads to be connected with wirings, the wirings for connecting the pads and the inner ends of leads become longer by the length over the power source and ground lines, so that the gain is reduced and the noise characteristic is degraded.(b) In also the case of the conventional signal processing IC in which the power source line or the ground line is arranged between the LNA circuit and the pads, similarly to the foregoing, the length of the wiring is increased more, the gain is reduced and the noise characteristic is degraded with the power source line and the ground line arranged.